| Line 25: | Line 25: | ||
<math> | <math> | ||
| − | \ a_1 = \frac{1}{2\pi}\int_{2\pi}^{\infty} \left (-1 \right ) | + | \ a_1 = \frac{1}{2\pi}\int_{2\pi}^{\infty} \left (-1 \right ) |
\frac{t^{2}}{ \left(2 \right )!}e^{-j\omega_0t}\, dt | \frac{t^{2}}{ \left(2 \right )!}e^{-j\omega_0t}\, dt | ||
</math> | </math> | ||
Revision as of 12:47, 26 September 2008
The function y(t) in this example is the periodic continuous-time signal cos(t) such that
$ y(t) = \ cos(t) $
where cos(t) can be expressed by the Maclaurin series expansion
$ \ cos(t) = \sum_{k=0}^\infty \left (-1 \right )^k \frac{t^{2k}}{ \left(2k \right )!} $
and its Fourier series coefficients are described by the equations below.
$ \ a_k = \frac{1}{T}\int_{T}^{\infty} y(t)e^{-jk\omega_0t}\, dt $
$ \omega_0 = \frac{2\pi}{T} = 1 $
With this information it is possible to determine the first fiew coefficients of the Fourier series of the signal, as seen below.
$ \ a_1 = \frac{1}{2\pi}\int_{2\pi}^{\infty} \left (-1 \right ) \frac{t^{2}}{ \left(2 \right )!}e^{-j\omega_0t}\, dt $
